I've done exactly that and it turns out fine. Construct the lasagna completely, wrap tightly in foil or plastic and refrigerate. Remove wrappings the next day and bake - absolutely perfect. Lasagna is one of the things I make when i really do want to have all the heavy lifting out of the way ahead of time. I've made that very lasagna many times - love it.

You're welcome. I want to add that the reason reheated leftovers separate is that the whole business has already been cooked - a very different result than first-time cooking. I happen to have a frozen one of those stashed in the freezer for some lasagna emergency in the future - I made it in the fall after a successful mushroom-picking expedition that yielded an excess of fresh porcinis. Maybe will have to bake it soon...

Thanks again. I can't try it this time - too close to event - but will try freezing it as that would be really convenient. My one gripe with this delicious dish is that it requires a lot of dishes/pots in the preparation so having it all ready to heat would truly be a time saver.